Billie Eilish opened up honestly about her experiences with Tourette Syndrome, which she was diagnosed with at the age of 11. Tourette Syndrome is a neurological condition that manifests in different “tics” for people, which can include a wide variety of sudden movements or noises.

Eilish spoke with David Letterman on a multitude of topics for his Netflix series My Next Guest Needs No Introduction. It first comes up when Eilish twitched in the interview, and Letterman mistook the motion for reacting to a fly. Eilish responded with, “no I’m tic-ing,” and said that the production crew’s lights sometimes cause her to tic more.

“The most common way that people react is they laugh. because they think I’m like trying to be funny,” Eilish said. She admitted the common reaction always leaves her, “incredibly offended,” but she still doesn’t mind discussing it because “it’s very, very interesting. And I am incredibly confused by it.”

She was very candid with Letterman, and even mentioned some examples of tics she has. “I wiggle my ear back and forth, and like raise my eyebrow, and click my jaw,” Eilish lists, and adds many other subtle motions that, “You would never notice if you were just having a conversation with me, but for me, they’re very exhausting.”

Eilish also mentioned that she doesn’t tic nearly as much while doing activities where she’s “focusing” like performing or horseback riding, so it’s great she has an occasional respite from it. “I have made friends with it. And so now, I’m pretty confident in it,” Eilish concluded.

Here’s another clip of their interview, which shows Eilish and her brother Finneas giving Letterman a glimpse of their production process.

Read more about: